Construction of multi-component supramolecular architectures of bile acids and cinchona alkaloids through helical-pitch-synchronized crystallization

Abstract

Molecular assemblies based on helical motifs are of substantial interest from the view point of fundamental science as well as application. In this study, we propose a new class of organic crystal, that is, heteroH-MOC (multi-component organic crystal containing different kinds of helical motifs consisted of different components), and describe successful construction of heteroH-MOCs with P2₁ and P2₁2₁2₁ space groups by using steroidal bile acids and cinchona alkaloids. In the P2₁ crystals, two kinds of helices composed of the steroid and alkaloid are arranged in a parallel fashion, while, in the P2₁2₁2₁ crystals, those are in a perpendicular fashion. It is remarkable that, in such systems, particularly in the latter crystals, components ingeniously achieved highly-ordered synchronization of periodicity (helical pitches r and periodic distances in the array of helices p), which is first demonstrated in this study through hierarchical interpretation of the crystal structures.